Bourdon tube gauge



Oct. 27, 1953 o. w. 5155 BOURDON TUBE GAUGE Filed Dec. 20, 1350.

INVENTOR.

0770 14 H6166 BY Patented Oct. 27, 1 953 UNITED STAT PATENT UFF 2,656,723 fidfiitfidfi" TUBE Gifiiiii one w. Heise, Newmwmcairn; Aiithltidit iic'h'it'teo, 1956, sets! status- 5 claims; v 1

rm mveiluearemtestc Bof'rdontube type, and particularly to a and improves device for insuring" the complete; re:

nlcva or air I I I II gauge" is" used to measure the pressure of liquid} Various met as have been employed in the past to'veiit Bourd'on tubes and anta: t e r minute; to an; estent tu purposes for"; which they were designed. n a'i'fi'ably, howeveatney" allfaildtovent thetube completely"; Trapp g the attenuat on or any air within the-Bo or don; tube sets up a cond tion I I I actior'i'vari's conside'rablyovr its tangent move nient'relativly'toiits action-when'thtube recon-1 pletely ventedL when th ja e is first} calibrated at the rectory, its tuhe'is completly vented, censequnt1y,sutse uen use' o f the gauge with entrapped; air in the tubeproducesinaccurat readmes. Additionally, when e'ntrapp air ace-unlulates in a Bourdontube, sudden'reversalsof pres: sure'c'ausewild fluctuations of the tube end with seq dan er Q ma o he d isa mi tiplyin mechanism. Another very important reason for requiring complete venting of the B ourdtin t'ube is that air bubbles-often form with-' irl' the connecting tube that Iea'dS tO the B'bu'fdtin tube; The passage through thisco'nnecting tube is usually of much smaller diameter than" the Bourdon tube,: and; consequent y bubbles that form therein provide a resistane to the flow of I liguid'in; the connecting tube'because of theforce requiredto overcome theadhe'sionjot an apparent skin or the bubble to'the sidesof the connecting tube; Iri other wordsya nieiiiScus like condition is encountered when bubbles form in the connecting tube that absorbs a certain amount of the force applied by the medium being measured in moving the liquid in the connecting tube. Accordingly, extremely accurate pressure measurements under these conditions are unobtainable.

The principal object of this invention is to provide a construction that will completely vent the tube of a Bourdon gauge without in any way affecting the delicate movement of the free end of the tube.

Other objects include the provision of a Bourdon tube gauge embodying a venting device for the tube that can be operated without dismantling the gauge; the provision of such a gauge in which the venting device can, with facility, be located at any convenient point of the gauge housing such as, for example, at any location on the back or side of the gauge housing, and even remotely from the gauge, as for example on the front of a panel board supporting the gauge; and

whereirt the tube along line 2*-2 of Fig;

Figure 2 is a sectibiiai elevation view tater Referring p n 1-,;axii nlet tois Mounted within the hbusing I o'f gauge with' as tron- I2 extending through housing wallt6 which a; connection is" r'ri e with the vessei' con taining a medium, the pres re ofwhich is to be" measured. curved eb'rlneeuh tube' f3" is conne'iified tbinlet NY a* uhiofi fitting H". A threaded socket I5 is" alttac'h'd to' a casting it that is firmly anchored to theback of the augehtusmg The Bourdon' t'ub n is c'onventidna'r desi n having an emerges and f8 thrade'dintd of thefsoclgetl5.- Th'eciifve'd tube lthas its' 'one he airman-stat tes the socket I15 and pro'jecti' iht'o'the' enlarged end F8 or tube IT. The" inte nal diameter or 1311's" f iiiuc'li smallervalue'thant'hat of tube IT. A empres sion nut I9 acts uphn a" compression: sleeve to" firmly hold' tube r3- sealing relation to the Boiiido'n t'ub H I The opposite" end d f the" Bourdonf tube 11 is al's'denla'igedaiid threads-a tdr'ceive ai'tlireadd sleeve 2|. A union nipple 22 having a conical seat is held in sealing relation with a mating seat formed at the free end of the tube I! by a nut 23. The nipple 22 is provided with a relatively small hole extending throughout its length, which is counterbored and threaded to receive a venting screw 22. A supplementary vent including a very fine, hollow tube 24 passes through the side wall of nipple 22 and is hermetically sealed thereto. The small hollow tube 24 extends inwardly of the tube ll to a point where its inlet end within the tube is at the highest elevation within tube i! when the tube is in its normal position for use. The remainder of the hollow tube 24 is coiled in the form of a coil spring having sufficient convolutions to permit its outlet end to be located at any convenient point within the housing H, or even to extend outwardly of such housing and still permit the free, uninhibited action of the free end of tube l1.

Although the outer end of tube 24 may be located with facility at any convenient point within or without the housing II, it is shown by way of example as being attached to a fitting 25 (Fig. 2) that is mounted on the interior of the back wall of housing I l and extending outwardly therefrom. The fitting 25 includes a bore 26 and a threaded counterbore 21, the bottom of the latter of which forms a conical seat 28. A venting valve 29 is threaded into the counterbore 2'1 and it includes a conical seat that mates with seat 28.

From the foregoing, it is evident that the venting device, by virtue of the location of the end of tube 24 within tube I1, permits complete'venting of the Bourdon tube l1, and that such venting mechanism in no way inhibits the free action of tube I1. Furthermore, it is evident that the venting screw 29 can be operated from the exterior of the gauge housing and even on a panel board supporting the gauge, thereby making it possible to vent the gauge at frequent intervals without dismantling the gauge.

Although the various features of the invention have been shown and described as applied to one embodiment of the invention, it is evident that certain features may be used without others without departing from the principles of the invention.

What is claimed is:

1. In a Bourdon tube gauge, a housing; an inlet; a Bourdon tube connected tosaid inlet and having a free end opposite the inlet end at a lower elevation when in its normal operating position than other portions of said tube; and vent I means having an inlet and an outlet, said inlet being located within said tube at the highest point of elevation therein when said gauge is in its normal operating position.

2. In a Bourdon tube gauge, a housing; an inlet; a Bourdon tube connected to said inlet and having a free end opposite the inlet end at a lower elevation when in its normal operating position than other portions of said tube; a device adapted to be mounted at any point within said housing and extending to the exterior thereof; and a resilient tube extending from said device to the interior of said Bourdon tube and having an inlet at a point therein at the highest elevation within the interior of said tube when said gauge is in its normal operating position.

3. In a Bourdon tube gauge, a housing; an inlet; a Bourdon tube connected to said inlet and having a free end opposite the inlet end at a lower elevation when in its normal operating position than other portions of said tube; a fitting adapted to be located at any convenient point relatively to said gauge; a venting screw in said fitting; and a hollow tube extending from said fitting to a point Within said Bourdon tube at the highest point of elevation within said Bourdon tube when said gauge is in its normal operating position.

4. In a Bourdon tube gauge, a housing; an inlet; a Bourdon tube connected to said inlet and having a free end opposite the inlet end at a lower elevation when in its normal operating position than other portions of said tube; a fitting adapted to be located at any convenient point relatively to said gauge; a venting screw in said fitting; and a hollow tube of relatively small diameter compared to that of said Bourdon tube extending from the point of highest elevation within said Bourdon tube to the exterior thereof, said hollow tube being coiled in the form of a spring and attached to said fitting.

5. In a Bourdon tube gauge, a housing; an inlet; a Bourdon tube connected to said inlet and having a free end opposite the inlet end at a lower elevation when in its normal operating position than other portions of said tube; a hollow nipple attached to the free end of said Bourdon tube; a venting screw attached to said nipple; an auxiliary venting device including a coiled hollow tube of smaller outside diameter than the internal diameter of said hollow nipple, the free end of said coiled tube extending through said hollow nipple into said Bourdon tube to the point therein of highest elevation when said gauge is in the position to be used; a fitting adapted to be located at any convenient location relatively to said gauge and to which the opposite end of said coiled tube is connected; and a venting screw within said fitting and accessible from the exterior of said gauge.

OTTO W. HEISE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,322,463 Nelson Nov. 18, 1919 1,363,415 Hopkins 1 Dec. 28, 1920 2,470,714 Nevius May 17, 1949 FOREIGN PATENTS Number Country Date 87,805 Germany Sept. 20, 1895 111,614 Germany July 6, 1900 218,416 Great Britain July 10, 1924 

